In U.S. Pat. Nos. 4,046,889 and 4,105,776, issued Sept. 6, 1977, and Aug. 8, 1978, respectively, Ondetti and Cushman have disclosed that a group of proline derivatives and related analogs which have the general formula ##STR4## have angiotensin converting enzyme inhibiting activity and are useful as antihypertensive agents. Also in copending application Ser. No. 926,177, filed July 20, 1978, Ondetti and I have disclosed that a group of phosphonoacylprolines and related analogs which have the general formula ##STR5## have angiotensin converting enzyme activity and are useful as antihypertensive agents too.
It has now been found that a group of new pyrrolidine and piperidine derivatives which have the general formula I have angiotensin converting enzyme inhibiting properties and they are useful as antihypertensive agents.